[Interpreter] Optimize code of the form 'if (x === undefined)'.

test/cctest/interpreter/bytecode_expectations/Generators.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 wrap: no
 test function name: f
 
 ---
 snippet: "
@@ skipping 262 matching lines @@
   [51, 224, 230],
 ]
 
 ---
 snippet: "
   function* f() { for (let x of [42]) yield x }
   f();
 "
 frame size: 18
 parameter count: 1
-bytecode array length: 754
+bytecode array length: 751
 bytecodes: [
                 B(Ldar), R(new_target),
                 B(JumpIfUndefined), U8(33),
                 B(CallRuntime), U16(Runtime::k_GeneratorGetContext), R(new_target), U8(1),
                 B(PushContext), R(4),
                 B(ResumeGenerator), R(new_target),
                 B(Star), R(3),
                 B(LdaZero),
                 B(TestEqualStrictNoFeedback), R(3),
                 B(JumpIfTrue), U8(60),
@@ skipping 173 matching lines @@
                 B(Star), R(9),
                 B(LdaSmi), I8(1),
                 B(Star), R(8),
                 B(LdaTheHole),
                 B(SetPendingMessage),
                 B(Star), R(10),
                 B(LdaContextSlot), R(1), U8(9), U8(0),
                 B(Star), R(11),
                 B(LdaZero),
                 B(TestEqualStrict), R(11), U8(16),
-                B(JumpIfTrue), U8(153),
+                B(JumpIfTrue), U8(150),
                 B(LdaContextSlot), R(1), U8(7), U8(0),
                 B(Star), R(11),
                 B(LdaNamedProperty), R(11), U8(9), U8(17),
                 B(StaContextSlot), R(1), U8(11), U8(0),
                 B(LdaContextSlot), R(1), U8(11), U8(0),
-                B(Star), R(11),
-                B(TestUndetectable), R(11),
+                B(TestUndetectable),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(127),
                 B(LdaContextSlot), R(1), U8(9), U8(0),
                 B(Star), R(11),
                 B(LdaSmi), I8(1),
                 B(TestEqualStrict), R(11), U8(20),
                 B(JumpIfFalse), U8(69),
                 B(LdaContextSlot), R(1), U8(11), U8(0),
                 B(TestTypeOf), U8(5),
                 B(JumpIfFalse), U8(4),
@@ skipping 115 matching lines @@
   SYMBOL_TYPE,
   ONE_BYTE_INTERNALIZED_STRING_TYPE ["next"],
   ONE_BYTE_INTERNALIZED_STRING_TYPE ["done"],
   ONE_BYTE_INTERNALIZED_STRING_TYPE ["value"],
   FIXED_ARRAY_TYPE,
   ONE_BYTE_INTERNALIZED_STRING_TYPE [".catch"],
   FIXED_ARRAY_TYPE,
   ONE_BYTE_INTERNALIZED_STRING_TYPE ["return"],
   ONE_BYTE_INTERNALIZED_STRING_TYPE [""],
   FIXED_ARRAY_TYPE,
-  Smi [566],
+  Smi [563],
 ]
 handlers: [
-  [51, 678, 684],
+  [51, 675, 681],
   [146, 437, 443],
   [149, 393, 395],
-  [533, 549, 551],
+  [530, 546, 548],
 ]